EYE and smell tests could help detect Alzheimer’s disease years before it strikes, according to four independent studies.

Two used fluorescent compounds to detect deposits of the protein amyloid in the eye.

The authors of these studies believe the amount of amyloid found is a good indicator of how much is present in the brain, where it forms sticky clumps in those with Alzheimer’s.

Two other studies suggest a loss in the ability to detect odours could be an early sign of the disease.

Dr Simon Ridley, of Alzheimer’s Research UK, said: “It is difficult to diagnose Alzheimer’s disease accurately and, in many cases, by the time the symptoms have developed, damage has already been going on in the brain for a number of years.

This research is promising

Dr Simon Ridley, Alzheimer’s Research UK,

“A quick, cheap, non-invasive test to detect Alzheimer’s would be an important step in helping people to receive an early diagnosis .

“This research is promising but it is too soon to determine whether these types of tests will be useful for diagnosis of dementia .”

The results of the four trials were presented at the Alzheimer’s Association International Conference in Copenhagen.